A bidirectional synthesis of spiroacetals via Rh(<scp>ii</scp>)-catalysed C–H insertion
作者:Romain J. Lepage、Jonathan M. White、Mark J. Coster
DOI:10.1039/c7cc00459a
日期:——
Acyclic methylene acetals bearing two diazoester subunits have been converted to [5,5]-spiroacetalsviabidirectional C–H insertion under Rh(ii) catalysis.
Stereoselective bidirectional synthesis of spiroacetals via Rh(II)-catalysed double C–H insertion
作者:Romain J. Lepage、Mark J. Coster
DOI:10.1016/j.tet.2018.01.043
日期:2018.3
Rh(II)-catalysed double C–H insertion of methylene acetals bearing two diazo ester substituents is described. The diastereoselectivity of this bidirectional approach can be tuned through appropriate choice of catalyst, and chiral catalysts lead to products with up to 89% ee. The diastereoselectivity of the first cyclisation suggests that the second cyclisation proceeds via a non-concerted pathway.
Polyketo-enols and chelates. Part I. The formation and constitution of xanthophanic enol and the xanthyrones
作者:L. Crombie、D. E. Games、M. H. Knight
DOI:10.1039/j39670000757
日期:——
A new structure is proposed, on the basis of spectroscopic and chemical evidence, for the yellow compound diethyl xanthophanicenol formed when ethyl sodioacetoacetate and ethyl ethoxymethyleneacetoacetate are heated together. A mechanism of formation is outlined and supported. The new information is used to prepare various compounds of the xanthyrone class and two of these, 3,3′,3′,5-tetra-acetyl
�ber 7-Methyl-octadien-(2,6)-ol-(1), ein ?Apogeraniol?
作者:L. Willimann、H. Schinz
DOI:10.1002/hlca.19520350728
日期:1952.12.1
7-Methyl-octadien-(2,6)-ol-(1) wurde hergestellt und in 10-Methyl-undecatrien-(3,5,9)-on-(2) übergeführt. Aus diesem „Apopseudojonon” liess sich durch Behandlung mit Phosphorsäure unter den üblichen Bedingungen kein cyclisches Isomeres gewinnen, da Zersetzung in Kohlenwasserstoffe und Harze eintrat.